This invention relates to a sheet feeding apparatus for use in a printer, a copy machine, etc. for feeding, one by one, sheets of paper contained in a sheet cassette or a sheet tray.
In the prior art, when feeding, one by one, stacked sheets of paper contained in a sheet feeding device such as a sheet cassette or a sheet tray, an end of the uppermost one of the sheets is pressed against a pickup roller by the force of an intermediate plate spring, and forwarded.
If, in this structure, used paper (one surface of which is printed with data, and the reverse surface of which is to be used) or recycled paper is reused as part of environmental protection, it is very possible that several sheets will be picked up simultaneously or no sheets will be picked up. This is because of high or uneven friction between sheets of this type.
In light of the above, Japanese Patent Application KOKAI Publication No. 9-278200, for example, discloses a technique for picking up only the uppermost one of sheets contained in a sheet tray, with the other sheets held by holding means.
When stacking used paper sheets as described above in a sheet feeding mechanism, however, end portions of the sheets are liable to be deformed, since it is very difficult to perfectly align these sheets before they are contained in the feeding mechanism, and hence they must be stacked therein more or less forcibly. As a result, defective feeding such as simultaneous feeding of several sheets, no feeding of sheets, etc. may often occur. To avoid such defective feeding, it is necessary to sufficiently align the sheets beforehand by, for example, joggling them, which requires a lot of time and effort. Because of this inconvenience, the ratio of reuse of used paper is kept low and environmental protection is not substantially enhanced.
It is the object of the invention to provide a sheet feeding mechanism and a sheet feeding method, which can prevent deformation of end portions of paper sheets, thereby facilitating supplement of paper sheets and eliminating defective feeding of paper sheets.
To attain the object, the invention provides a sheet feeding mechanism comprising: a first containing section for containing paper sheets that are not aligned; a sheet feeding section for feeding the paper sheets, contained in the first containing section, at a low speed that enables the paper sheets to be separated from each other; a second containing section for containing the paper sheets supplied by the sheet feeding section; an aligning section for aligning the paper sheets, contained in the second containing section, in units of a predetermined number of paper sheets; a movement section for moving the paper sheets aligned by the aligning section so that their alignment is maintained, when the second containing section is filled with the aligned paper sheets; and a third containing section for containing the aligned paper sheets moved by the movement section so that their alignment is maintained, and for feeding, one by one, the aligned paper sheets contained therein.
The invention also provides a sheet feeding mechanism comprising: a first containing section for containing paper sheets that are not aligned; a sheet feeding section for feeding the paper sheets, contained in the first containing section, at a low speed that enables the paper sheets to be separated from each other; a conveyance section for conveying paper sheets fed by the sheet feeding section; a second containing section for containing paper sheets conveyed by the conveyance section; an aligning section for aligning paper sheets, contained in the second containing section, in units of a predetermined number of paper sheets; a movement section for moving the paper sheets aligned by the aligning section so that their alignment is maintained, when the second containing section is filled with the aligned paper sheets; and a third containing section for containing the aligned paper sheets moved by the movement section so that their alignment is maintained, and for feeding, one by one, the aligned paper sheets contained therein.
The invention further provides a sheet feeding method comprising: a first step of containing, in a first containing section, paper sheets that are not aligned; a second step of feeding the paper sheets, contained in the first containing section, at a low speed that enables the paper sheets to be separated from each other; a third step of containing, in a second containing section, the paper sheets fed in the second step; a fourth step of aligning the paper sheets, contained in the second containing section, in units of a predetermined number of paper sheets; a fifth step of moving the paper sheets aligned in the fourth step so that their alignment is maintained, when the second containing section is filled with the aligned paper sheets; and a sixth step of containing the aligned paper sheets moved in the fifth step so that their alignment is maintained, and feeding, one by one, the aligned and contained paper sheets.